Famed activist investor and onetime corporate raider Carl Icahn is back in the news in a big way — and this time he’s set his sights on the mother of all technology targets: Apple. Icahn, a legendary Wall Street billionaire, announced Tuesday that he has amassed a “large” position in the world’s biggest technology company because he believes it to be “extremely undervalued.”

In a message on Twitter and in subsequentmediainterviews, Icahn said that he had spoken to Apple CEO Tim Cook about his belief that the company should immediately buy back more of its stock, which would have the effect of boosting Apple’s share price. He told Reuters that such a buyback could help push Apple’s stock price, which has languished below $500 for much of 2013, as high as $700 per share.

Icahn, a 77-year-old Queens, New York-native with a reputation as a bare-knuckled business brawler, has a long and colorful history of taking large positions in companies that he believes to be undervalued and then agitating for change. Last year, Icahn acquired a large stake in online video company Netflix, which has generated a $1 billion gain for the mogul, according to the Wall Street Journal. Icahn also holds an estimated 9% stake in struggling PC maker Dell.

Icahn’s newly disclosed Apple stake — which the Journalvalued at more than $1.5 billion — puts pressure on the company to return more of its $147 billion cash hoard to investors. In April, Cook said that Apple plans to return $100 billion to shareholders by the end of 2015. Icahn’s stake also highlights ongoing analyst concerns about Apple’s ability to produce new, breakthrough gadgets. Apple hasn’t launched a brand new product line since it released the first iPad model in 2010. Wall Street concerns about Apple’s ability to innovate have helped drive down the company’s stock price by more than 25% over the last year.

In the short term, Icahn’s interest in Apple appears primarily financial. By simply announcing his stake, Icahn helped push Apple shares up more than 5% on Tuesday to $489.57, the highest level in over six months. This so-called “Icahn bump” increased Apple’s market value by about $17 billion. Icahn wants Apple to take advantage of low interest rates to borrow a whopping $150 billion at 3% interest, to be used to buy back its own stock. “If Apple does this now and earnings increase at only 10%, the stock — even keeping the same multiple, currently should trade at $700 a share,” Icahn told Reuters.

Although Icahn didn’t explicitly address Apple’s innovation “issue,” a buyback, coupled with a few hit new products, could push Apple shares even higher than $700. He told the Journal that his son Brett Icahn and investment partner David Schechter convinced him to make the large investment in Apple, in part because they are enthusiastic about the possibility that the company could unveil breakthrough new products, including the long-rumored smart-watch, and potentially, a category-busting new television product.

Meanwhile, Apple is reportedly preparing to refresh its existing iPhone and iPad lines in time for the holidays, according to Bloomberg. An updated iPhone will be unveiled at a Sept. 10 event, with new iPad models to be introduced later in the fall, Bloomberg reported, citing multiple sources with knowledge of the plans. It’s very unusual for Apple launches to be telegraphed in the press this way, but Apple, or its proxies, could be signaling to consumers that the wait for new products may soon be over.

“To drive growth you need to have that next iPhone and iPad refreshed,” Brian Marshall, an analyst at ISI Group in San Francisco, told Bloomberg. The iPhone and iPad accounted for almost 70% of the company’s sales last quarter. Apple had a head start on rivals with the iPhone and iPad, which effectively launched the smart phone and tablet mass markets, but the company faces growing competition from Samsung, Google’s Motorola division, and other hardware companies. Apple’s share of the tablet market slid to 32% last quarter from 60% a year earlier, according IDC market-research data cited by Bloomberg.

Icahn’s use of Twitter on Tuesday to broadcast his massive Apple position raised eyebrows on Wall Street, but in a Securities and Exchange Commission filing on Monday, and in a statement on his firm’s website, the billionaire served notice that he might be using the 140-character medium. “We currently have a large position in APPLE,” Icahn tweeted on Tuesday. “We believe the company to be extremely undervalued.” A few minutes later, he added: “Had a nice conversation with Tim Cook today. Discussed my opinion that a larger buyback should be done now. We plan to speak again shortly.”

For now at least, relations appear to be cordial between Icahn, who is worth an estimated $20 billion, and the tech giant. But that could change if the billionaire shareholder feels his wishes aren’t being heeded. Icahn had previously disclosed to the SEC that he used Twitter to broadcast strongly worded messages about Michael Dell’s plan to take the ailing PC giant he founded private. Icahn, who owns about 9% of Dell shares, opposes such a plan. In one such message, Icahn wrote that “a reason Dell is undervalued is due to a major liability that can be easily removed — Michael Dell.”

Cook is no doubt aware of Icahn’s reputation as a pugnacious financial operator. In a statement emailed to TIME, an Apple spokesman said: “We appreciate the interest and investment of all our shareholders. Tim had a very positive conversation with Mr. Icahn today.”

Cool, it sounds like this moron can afford to lose a whole bunch of money. And sure, he wants Apple to do whatever they can to boost the price of HIS shares so that he can cash out. Because, you know, he needs more money.